Process of treating photographic film and product thereof



Patented Oct. 25, 1932 UNITED STATES PATENT orrics KENNETH C. D. HICKMAN, OF ROCHESTER, NEW YORK, ASSIGNOB TO EASTMAN KODAK COMPANY, OF ROCHESTER, NEW YORK, A COBI'ORATION OF NEW YORK PROCESS OF TREATING PHOTOGRAIHIC FILM AND PRODUCT THEREOF ll'c Drawing.

7 wet condition during the photographicfluid treatment'prior to drying. Still another object of the invention is to provide a process which will lubricate the film and at the same time impart to it the property of remaining flat and flexible, even in a dry atmosphere.

Still another object is to provide a process which will accomplish the necessary lubrication and the flexibility of the film without impairing the color or transparency of it. Yet another object is to provide, as an article of manufacture, a flexible photographic film provided with a gelatinous coating which contains a useful supply of lubricant in the gelatinous layer, said lubricant also renderlng said gelatinous layer flexible in a dry atmosphere, and non-deliquescent in a damp atmosphere. Other objects will hereinafter ap ear.

shallnow describe the application of my invention to the treatment of motion picture -film, because that is its present maximum field of usefulness, but it will be understood that the invention can be employed in treating other kinds of photographic films. Motion picture films, when subjected to the customary photograp'hic'operations of exposure, development, fixing, washing, drying, etc., often exhibit a tendency to stick in the gates and other parts of the projecting apparatus, especially if the film is to be projected shortly after said manipulations are finished. The colloid picture-layer, especially if gelatinous, plays a particularly prominent part in connection with this trouble. Moreover, such films, under very dry conditions, which are often met with in practice, tend to become obj ectiona'bly curly or kinked, so that they Application filed January 30, 1928. Serial No. 250,852.

do not lie flat in the gate of the projector, and the picture-layer may even become brittle.

It is, therefore, highly desirable to be able to lubricate motion picture films, particularly the picture-layer thereof, and at the same time enhance the flexibility or flatness of the film, without making it liable to deliquesce in moist atmospheres. Preferably, the process should be carried out during the fluid treatments of the film and before drying, to avoid an extra. processing or drying operation.

.I have found that the desired results may be obtained by treating a photographic film having a water-permeable colloid layer, such as gelatin, with an aqueous solution of a lubricant of low volatility, said lubricant being preferably one that readily penetrates the interior of the gelatin layer, and increases the flexibility of the latter under dry conditions, without causing deliquescence under humid conditions. When the solution of Inbricant is applied to the film, theexcess is removed and the film dried while a useful amount, of the lubricant is retained in the picture-layer. 'Ordinary lubricating oils do not penetrate gelatin readily, and are insoluble in water. But I have found that certain soaps, which are soluble in soft water, will penetrate gelatin readily and upon remaining therein, will impart flexibility to the layer, as well as supply lubricant to the surface of the layer. Moreover, these soaps do not render the film deliquescent in humid atmospheres, as glycerin, which has heretofore been proposed, tends to do. In practice I have found that an aqueous solution of Turkey red oil (an alkali salt of sulfonatedcastoroil) serves excellently as a combined lubricant and non-deliquescent flexibilizer for gelatin layers. While the treatment of the film with my solutions may be carried on when it is wet, nevertheless, it is effective as an additional treatment on otherwise dried and completed film, although this makes an extra step. which is not preferred.

I shall now describe an illustrative application of my invention, but it will be under- 5 stood that the latter is not limited to the details thus given, except as indicated in the appended claims. 15 parts by volume of Turkey red oil are stirred into 1000 parts by volume of water, along with 2 parts by volume of a strong aqueous ammonia solution. This gives a substantially clear bath with soft water, which it is, of course, desirable to use. In this bath the motion picture film to be treated is immersed for about five minutes. It will be seen that this bath may be the last one of a series of photographic fluid treatments prior to drying in a continuous processing machine. Upon issuing from the batthe excess of the liquid is removed from the film, say by air squeegeeing,one useful method of doing this being described in my British Patent No. 217,642, accepted June 17, 1924 Pneumatic apparatus for removing adherent liquids from the surface of photographic films and the like. When the squeegeed film is dried in the customary apparatus, it will be found that it remains flat and flexible and will retain these properties even under adverse dry conditions. The softened or plasticized gelatin layer does not become excessively hygroscopic or deliquesce if the film is subsequently used in a damp atmosphere. In other words, a flexibility, comparable to that obtained with glycerin, is provided by my treatment, and yet the harmful moisture-attracting qualities of glycerin are avoided. Thetransparency and color of the film are not impaired. The film is practically self-lubricating and behaves as though the lubricant in the gelatin acted as a reservoir from which any deficiency at the surface of the gelatin may be made up. Even if the film be washed in carbon tetrachlorid, the treated film will retain its superior flexlbility and self-oiling properties.

In many cases the gelatinous picture-layer has been hardened with alum and enough aluminous material may remain in the gelat1n to react with the Turkey red oil and form an aluminum salt of the latter. If an insuflicient concentration of Turkey red oil is used in treating alum-hardened film, the latter may become somewhat tacky, deficient in mechanical strength, and poorly lubricated. If, however, an adequate concentration of Turkey red oil is used. the troublesome aluminum-oil compound is dissolved and the'same beneficial lubricating-plasticizing effects are obtained, as described above. While the ranges in concentration of Turkey red oil in the alkaline aqueous bath will vary in accordance with the presence or absence of aluminous material in the gelatin, I have found it preferable to employ an aqueous solution containing from 1% to 10% by volume of the Turkey red oil, the solution being clarified by an alkali, as ammonia.

The water for milking up the above described bath may be softened by treatment with zeolites in the known way. Furthermore, instead of using the solution as a bath, it may be impinged or sprayed upon the film in the processing machine prior to squeegeeing and drying.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In the process of treating photographic film having a water-permeable colloid picture layer, applying to said layer an aqueous solution of a lubricant of low volatility, and drying said layer while it retains some of said lubricant.

2. In the process of treating photographic film having a gelatinous picture layer, applying to said layer an aqueous solution of a lubricating soap, and drying said layer while it retains some of said lubricant.

3. In the process of treating photographic film having a water-permeable gelatinous picture layer, applying to said layer an aqueous solution of Turkey red oil, and drying said layer while it retains some of said lubricant.

4. In the process of treating photographic film having a water-permeable colloid picture layer, applying to said layer a substantially colorless aqueous solution of a lubricant of 100 low volatility, capable of flexibilizing said layer, and drying said layer. to leave therein a transparent, substantially colorless residue of said lubricant.

5. In the process of treating photographic film having a water-permeable colloid picture layer, applying to said layer, while wet, an aqueous solution of a lubricant of low volatility, removing the excess of said solution, and drying said layer while it retains some of said lubricant. Y

6. In the process of treating photographic film havinga. water-permeable gelatinous picture layer containing alum residues, applying to said layer an alkaline aqueous solution of Turkey red oil in a concentration which dissolves the aluminum compounds formed with said alum residues, and drying said layer while it retains some of said oil. 2

7. As an article of manufacture a'photographic film comprising a flexible support and a gelatinous picture layer having permeated therethrough a transparent lu'bricating compound which renders said layer sup- 1 5 ple, even in dry atmospheres, without deliquescing in moist atmospheres.

8. As an article of manufacture a photographic film comprising a flexible, transparent cellulosic supporting layer, and a gela- 130 tin picture-layer, the latter containing uniforinly permeated therethrough a transparent, colorless residuum of a In ricating soap which also renders said layer supple.

9. As an ,article of manufacture a photographic motion picture film comprising a transparent, flexible, supporting layer of a colloidized cellulosic compound, and a gelatin picture-layer having distributed therein a substantially transparent, colorless residuum of Turkey red oil, which renders said layer self-lubricating and supple, without causing deliquescence;

Signed at Rochester, New York this 26 day of January, 1928.

- KENNETH C. D. HIGKMAN. 

